feat: add Docker deployment configuration

- Add server Dockerfile with multi-stage build
- Add frontend Dockerfile with Nginx
- Add docker-compose.yml for orchestration
- Add Nginx config with SSL support
- Add deployment documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,13 @@
+node_modules
+dist
+.git
+.gitignore
+*.md
+!DEPLOY.md
+.env
+.env.local
+*.log
+.DS_Store
+coverage
+.vscode
+.idea